Tissue modification devices and methods

ABSTRACT

Described herein are devices, systems and methods for cutting tissue in a patient. In some embodiments, a tissue modification region of a device includes a pair of flexible elongate cutting members extending along the length of the tissue modification region. Each elongate cutting member may be configured to cut a discrete trough into tissue to a depth that is greater than the thickness of the cutting member. In some embodiments, the device includes a spacer. The spacer may be sized and configured to operate in one of two modes. A first mode, in which the spacer is coupled to the cutting members such that it holds a portion of each of the two cutting members a distance from one another, and a second mode, in which at least a portion of the spacer is moved away from a cutting member to allow the cutting members to cut further into tissue.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to U.S. Provisional ApplicationNo. 61/175,323, titled “TISSUE MODIFICATION DEVICES”, filed on May 4,2009; U.S. Provisional Application No. 61/254,638, titled “SPINAL BONECUTTING DEVICES AND METHODS”, filed on Oct. 23, 2009; and U.S.Provisional Application No. 61/285,188, titled “SPINAL BONE CUTTINGDEVICES AND METHODS”, filed on Dec. 10, 2009.

This patent application is also a continuation-in-part to U.S. patentapplication Ser. No. 12/496,094, titled “ACCESS AND TISSUE MODIFICATIONSYSTEMS AND METHODS”, filed on Jul. 1, 2009, which claims the benefit ofU.S. Provisional Application No. 61/077,441, titled “INNER SPINOUSDISTRACTION ACCESS AND DECOMPRESSION SYSTEM,” filed on Jul. 1, 2008.

This patent application is also a continuation-in-part to PCTApplication No. PCT/US09/50492, titled “TISSUE MODIFICATION DEVICES”,filed on Jul. 14, 2009, which claims priority to U.S. ProvisionalApplication No. 61/080,647, filed Jul. 14, 2008; U.S. ProvisionalApplication No. 61/081,685, filed Jul. 17, 2008; and U.S. ProvisionalPatent Application No. 61/163,699, filed Mar. 26, 2009.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

FIELD OF THE INVENTION

Described herein are systems, devices, and methods of using them, forcutting spinal bone and soft tissue in a way that minimizes potentialdamage to surrounding tissue, and particularly the spinal nerves andvasculature. The methods, devices and systems described herein may beused as part of a spinal surgical procedure involving a complete orpartial removal of spinal bone or joint, such as a laminectomy,laminotomy, fascetectomy, pediculectomy, etc.

BACKGROUND OF THE INVENTION

Surgical intervention may require the manipulation of one or moremedical devices in close proximity to a nerve or nerves, which may riskdamage to the nerve tissue. For example, medical devices may be used tocut, extract, suture, coagulate, or otherwise manipulate tissueincluding tissue near or adjacent to neural tissue. Spinaldecompressions, are one type of procedure that may be preformed toremove tissue that is impinging on a spinal nerve. It would bebeneficial to be able to cut or manipulate tissue (and especially bone)in a way that avoids or protects nearby structures such as nerves, whileallowing precise removal of bone or portions of bones.

For example, a Transforaminal Lumbar Interbody Fusion (“TLIF”) procedureis a surgical technique to stabilize the spinal vertebra and the disc orshock absorber between the vertebras. In this procedure, lumbar fusionsurgery creates a solid structure (bone and/or interbody device) betweenadjoining vertebras, eliminating any movement between the bones. Thegoal of the surgery is to reduce pain and nerve irritation. Theprocedure typically involves removal of a great deal of spinal bone,e.g., by cutting through the patients back and removing the facet jointsto create an opening into which a spacer or interbody cage can beinserted and filled with bone graft material. Interbody devices such ascages or spacers are typically 8 mm wide to 15 mm wide. Pedicle screwsand rods or plates may then be used to fuse the vertebra.

It is common to do a laminectomy as part of the TLIF procedure, in orderto provide space for the insertion of the spacer or cage. Other, similarprocedures such as Posterior Lumbar Interbody Fusion (PLIF) proceduresalso involve cutting and removing a region of bone from the spine, suchas the removal of a portion of the inferior articulating process (IAP).Removal of these relatively large portions of bone may be difficult, andmay require cutting through a substantial amount of otherwise healthytissue. In addition, the effort of cutting through the bone may damagenearby tissue, including nerve tissue such as nerve roots which areintimately associated with the spine in the dorsal column region beingmodified. The risks and difficulties of the procedures described aboveand other such surgical procedure may be exacerbated by the need to makemultiple cuts in bone and other tissues, which are typically performedsequentially.

In addition, procedures such as these that involve cutting of spinalbone must be performed in difficult to reach regions, and the surgicalprocedures performed may necessarily need to navigate narrow andtortuous pathways. Thus, it would be of particular interest to providedevices that are extremely low profile, or are adapted for use withexisting low-profile surgical devices and systems. It would also bebeneficial to provide devices capable of making multiple, simultaneouscuts at different positions in the tissue (e.g., bone).

Described herein are devices, systems and methods that may address manyof the problems and identified needs described above.

SUMMARY OF THE INVENTION

Described herein are devices, systems and methods for cuttingpredetermined regions of a spine.

In general, the methods described herein include making two cuts throughbone in the dorsal spinal column (e.g., through the pedicles, lamina, orother bony regions of the spinal column). The cuts may be madesimultaneously (e.g., using a device having two cutting elements whichmay be arranged in parallel) or sequentially. The method typicallybegins with the delivery of a guidewire around the target bone region.The guidewire is passed into the body from a first location, around thetarget bone, and out of the body at a second location. The guidewire maybe positioned using one or more needles, cannula, etc. that can steerthe guidewire as it is inserted. This method is described in many of thepatents incorporated by reference above. The distal end of the guidewiremay be sharp, so that it can penetrate the tissue as the guidewire ispushed from the proximal end. The proximal end of the guidewire may beadapted to link securely (and removably) to the distal end of a cuttingdevice, such as a cutting wire saw.

After passing the guidewire around the target bone to be cut, anelectrode or other neural localization device (as described in some ofthe reference incorporated in their entirety above) may be used toconfirm that a nerve (e.g., spinal nerve) is not located between theguidewire and the bone to be cut, which could damage the nerve. Forexample, the distal end of a ribbon-shaped neural localization device(having a relatively flat and flexible profile) may be coupled via aguidewire coupling member to the distal end of the guidewire and pulledinto position around the bone, then stimulated by applying electricalcurrent to electrodes on the surface(s) of the neural localizationdevice to confirm that a nerve is not present. If a nerve is presentbetween the target bone and the neural localization device, theguidewire may be removed and repositioned, then the detection processrepeated. Other neural localization methods or devices may be used,including visual detection/confirmation of nerve location, detection byelectrical impedance measurements, ultrasound, or the like.

Once the guidewire is positioned in the desired pathway to be taken bythe cutting element for cutting the bone, a protective element (e.g.,cover, shield, etc.) may be positioned by pulling it into position usingthe guidewire. In some variations the neural localization device isconfigured as a shield or cover. For example, a shield or cover may be aflat, thin and flexible elongate (e.g., ribbon-shaped) body that can bepositioned using the guidewire. The protective element may include achannel or path for the guidewire. In some variations the protectiveelement may be pulled (e.g., pulled distally) into position using theguidewire after coupling the distal end of the protective element to theguidewire, and then the guidewire may be pushed proximally so that theproximal end of the guidewire extends back out of the patient and can becoupled to a second element (e.g., cutting element) while the distal endof the protective device remains in position. In some variations asecond guidewire may be passed along the same or a parallel pathwaythrough the tissue to position additional elements such as a cuttingelement. Channels in/on the protective element may assist with this.Alternatively, in some variations the protective element may bepositioned over the guidewire, without coupling to the distal end.

Once the pathway around the target bone to be cut has been determined(and in some variations protected), a cutting tool such a wire saw maythen be positioned by coupling the cutting tool to the end of theguidewire and pulling the guidewire to pull the cutting tool (e.g., wiresaw) into place. The cutting tool is optimally a thin, flexible cuttingtool that may be used bimanually, e.g., by pulling on both the proximaland distal ends of the device to cut the bone. Examples of cuttingdevices include reciprocating cutting devices, and some examples ofthese are described below. Cutting elements may be abrasive (e.g.,having an abrasive surface). A cutting element may be a wire saw, suchas a Gigli saw, as known in the art, which is adapted for use asdescribed herein. Cutting elements are not limited to mechanicalcutters. Other cutting elements may include electrical cutting elements,thermal (heat) cutting devices, or the like.

In some variations a separate guidewire is not used, but the cuttingelement acts as a guidewire. For example, the cutting element mayinclude an integrated guidewire at the distal end. In some variations,the guidewire may be adapted as a cutting element.

Once positioned around the target tissue, the ends of the cuttingelement may be grasped manually or grasped using an assist device, andthe cutting element may be activated (e.g., by manual reciprocation) tocut the bone. Cutting the bone typically means cutting completelythrough the bone. In variations in which the cutting element is coupledto a guidewire, the cutting element may be reciprocated by pulling onthe distal end of the guidewire.

Manual reciprocation of the guidewire may be performed from outside ofthe patient. The direction of pulling and/or reciprocation may be basedon the direction of cutting intended. For example, when it is desirableto cut the bone (e.g., the superior articulating process or SAP)laterally so that the cut extends in the lateral direction relative tothe spine, the proximal and distal ends of the cutting element extendingfrom the patient (or the portions of a guidewire or other wire connectedto the cutting element that extends from the patient and can be graspedto manipulate the device) are pulled so that the force vector applied bypulling on the two ends at an angle points in the generally lateraldirection. In general, the direction of cutting using a flexible wiresystem as described herein will be determined by the force vectorresulting as the ends of the flexible cutting element is pulled fromboth ends. The pulling force may be alternated—e.g., to reciprocate thecutting element against the tissue.

In some variations, an assist or guide element may be used to helpposition the cutting element as it is reciprocated against the spine.For example, an assist device or guide may push the cutting elementagainst the tissue, helping to control the direction of the cutting.

The methods described herein may include a device configured to allowsimultaneous cutting of two or more bone regions. For example, a devicefor cutting bone may include two parallel cutting elements that areseparated by a predetermined spacer or spaces. The distal and proximalend regions of the cutting elements are connected so that reciprocatingthe ends of the device will cause reciprocation of both cuttingelements. As mentioned, the cutting elements are typically flexible, andmay be connected so that they remain separated by a predetermine spacingeven when contacting bone or during positioning. For example, the twoparallel cutting elements may be separated by a distance of betweenabout 4 and 16 mm, or between about 6-14 mm, or between about 8-15 mm.The two (or in some variations, more than two cutting elements aretypically arranged along the long axis (length) of the device. In somevariations, the cutting elements may be approximately parallel oractually parallel. In some variation, the cutting elements are notparallel, for example, the cutting surfaces may be slightly angledrelative to each other, and the device may be configured so that thedistance between the cutting edges may be varied or altered.

In variations in which two or more cuts to remove a portion of bone aremade sequentially (rather than in parallel), the method may includecutting the first portion of the bone, then moving the cutting elementto the start of the second cut without removing the cutting element fromthe tissue. Thus, both sides of a cut to remove the bone may be madewithout removing the cutting element. Cutting a section of bonecompletely away without having to remove the flexible cutting element(e.g., wire) from the body is one advantage of the methods describedherein.

When two cuts are made sequentially as mentioned above, an additionalpositioning device may be used to push, pull or otherwise guide themiddle of the cutting element (e.g., the region looped around the bone)into position around the bone at the desired second cutting position.For example, a wire saw may be used to cut the SAP laterally, then,after cutting completely through the SAP, the bent portion of thecutting element in the tissue may be moved into position by pushing itor sliding it to the second location. An example of this is providedbelow. The positioning device may be a rigid or stiff member having adistal end configured to push or grasp the loop of the cutting element.Since the bone being cut will be removed, in some variations theprocedure includes the step of cutting through the tissue to expose thebone. One or more probes may inserted into this cut and used to positionthe wire either using a manipulating device once it has been loopedaround the tissue as desired, or to position the probes to pass theguidewire around the bone to be cut.

Although an opening into the bone may be formed to remove the boneregion cut away, it may be beneficial to pass the guidewire around thetarget bone from a separate (even minimally invasive) access point.Thus, the cut into the tissue to remove the bone may be kept relativelysmall (e.g., sufficiently large enough only to retrieve the bone that iscut away), while separate pathways for the wire saw may be formedthrough the tissue in the directions that the wire saw will bereciprocated. In other variations the procedure may be preformedsubstantially “open,” exposing a region of the bone, and allowingmanipulation of the ends of the guidewire and/or cutting element asnecessary to cut at the desired angles and remove the bone.

In some variations, the methods described herein are adapted for cuttinga region of a spinal facet (e.g., cutting on one side of a superiorarticulating process) specifically, to permit insertion of a device suchas a cage or spacer. Described below is a specific example of oneprocedure and variations of devices that may be used to perform theprocedure, as well as systems including such devices. In somevariations, the method and devices described herein are adapted forcutting bone to perform an osteotomy. For example, in scoliosisreduction surgery portions of bone are removed to aid in thestraightening of the spine. In some variations, the methods and devicesdescribed herein are adapted for cutting a spinous process or transverseprocess or any other suitable portion of bone.

Also described herein are improved devices for modifying tissue andmethods of using them. These devices may be included as part of a systemfor modifying tissue. The tissue modification devices described hereintypically include an elongate, flexible length and a tissue modificationelement coupled to the flexible element. The flexible element mayinclude an expanding mechanism that expands at least a portion of aflexible element from a first width to a second width. A tissuemodification device may include one or more of these features in anycombination.

Methods for modifying tissue as described herein may include one or moreof the following steps: inserting an elongate, flexible element having afirst width; advancing the flexible element until a portion of theflexible element is adjacent to a target tissue; expanding at least theportion the flexible element adjacent to the target tissue to a secondwidth; and modifying the target tissue with the flexible element.

The methods for modifying tissue described may alternatively include oneor more of the following steps: inserting a first elongate, flexibleelement into the patient at a first location; advancing the firstflexible element until a portion of the flexible element is adjacent toa target tissue; inserting a second elongate, flexible element into thepatient at the first location, a distance from the first flexibleelement; and modifying the target tissue with the flexible elements.

Any of the devices described herein may be used as part of a tissuedecompression (e.g., spinal decompression) method to modify tissue suchas soft tissue (e.g., ligamentum flavum, etc.) and hard tissue (e.g.,bone). In particular, these devices may be used as part of a spinaldecompression technique within a spinal foramen.

The devices described herein may be used as part of a guide-based accessand decompression system, including those previously described in any ofthe following patent applications and provisional patent applications,each of which is herein incorporated by reference in its entirety: U.S.patent application Ser. No. 11/250,332, titled “DEVICES AND METHODS FORSELECTIVE SURGICAL REMOVAL OF TISSUE” (filed Oct. 15, 2005), U.S. patentapplication Ser. No. 11/251,199, titled “DEVICES AND METHODS FOR TISSUEACCESS” (Oct. 15, 2005), U.S. patent application Ser. No. 11/375,265,titled “METHODS AND APPARATUS FOR TISSUE MODIFICATION” (filed Mar. 13,2006), U.S. patent application Ser. No. 11/405,848, titled “MECHANICALTISSUE MODIFICATION DEVICES AND METHODS” (filed Apr. 17, 2006), U.S.patent application Ser. No. 11/429,377, titled “FLEXIBLE TISSUE RASP”(filed May 4, 2006), U.S. patent application Ser. No. 11/538,345, titled“ARTICULATING TISSUE CUTTING DEVICE” (filed Oct. 3, 2006), U.S. patentapplication Ser. No. 11/687,548, titled “TISSUE REMOVAL WITH AT LEASTPARTIALLY FLEXIBLE DEVICES” (filed Mar. 16, 2007), U.S. patentapplication Ser. No. 11/687,558, titled “FLEXIBLE TISSUE REMOVAL DEVICESAND METHODS” (filed Mar. 16, 2007), U.S. patent application Ser. No.11/870,370, titled “PERCUTANEOUS SPINAL STENOSIS TREATMENT” (filed Oct.10, 2007), and U.S. patent application Ser. No. 12/127,535, titled“GUIDEWIRE EXCHANGE SYSTEMS TO TREAT SPINAL STENOSIS” (filed May 27,2008).

In particular, the devices described herein may be used as aguidewire-based system that is configured so that the device may bepulled into position and/or tensioned so as to be urged against atissue, and thereby modify the tissue. This configuration may bereferred to as a bimanual system, since both ends (e.g., the proximalend and the distal end of the device) may be tensioned or pulled tomodify the tissue. Tissue may be modified by removal or smoothing of thetissue, and may be performed by pulling the devices described hereinthrough the tissue so that the working surface (e.g., the blades on therungs) contacts one or more tissue surfaces.

Also described herein are delivery devices for delivering tissuemodification devices for removing tissue from a patient. In someembodiments, the device includes a ribbon shaped flexible elongate bodyhaving a width defined by a first edge and a second edge. In someembodiments, the first and second edges are substantially parallel. Thedevice may also include a first channel, configured to receive a firstelongate cutting member, disposed along a portion of the length of theelongate body, positioned toward the first edge of the elongate body,and a second channel, configured to receive a second elongate cuttingmember, disposed along a portion of the length of the elongate body,positioned toward the second edge of the elongate body. In someembodiments, the device may also include a guidewire coupler at thedistal end region of the elongate body.

In some embodiments, a first flexible elongate cutting member isdisposed within the first channel and/or a second flexible elongatecutting member is disposed within the second channel.

Also described herein are methods for delivering tissue modificationdevices for removing tissue from a patient. In some embodiments, themethods include the steps of inserting an elongate, flexible shield intothe patient at a first location; advancing the shield until a portion ofthe shield is adjacent to a target tissue; inserting a first elongate,flexible cutting element through the shield until a portion of the firstcutting element is adjacent to a target tissue; inserting a secondelongate, flexible cutting element through the shield, a distance fromthe first cutting element and substantially parallel to the firstcutting element, until a portion of the second cutting element isadjacent to a target tissue; and modifying the tissue with the flexibleelements.

In some embodiments, the methods include the steps of inserting a firstelongate, flexible cutting element until a portion of the first cuttingelement is adjacent to a target tissue; advancing an elongate, flexibleshield into the patient, wherein a portion of the shield is advancedover the first elongate, flexible cutting element; inserting a secondelongate, flexible cutting element through the shield, a distance fromthe first cutting element and substantially parallel to the firstcutting element, until a portion of the second cutting element isadjacent to a target tissue; and modifying the tissue with the flexibleelements. In some embodiments, the methods further include the step ofremoving the shield from the patient while leaving the cutting elementsin position within the patient.

In some embodiments, a bimanually controlled tissue modification devicehaving a tissue modification region for cutting tissue in a patientincludes a pair of flexible elongate cutting members extending along thelength of the tissue modification region. Each elongate cutting membermay have a thickness and each elongate cutting member may be configuredto cut a discrete trough into tissue to a depth that is greater than thethickness of the cutting member. In some embodiments, the deviceincludes a guidewire coupler distal to the tissue modification region ofthe device. The guidewire coupler may be configured to be coupled to aguidewire, e.g., at the proximal end of the guidewire, and the tissuemodification region may be actuated by pulling on a proximal handle onor connected to the device, and on a guidewire coupled to the distal endof the device. In some embodiments, the tissue modification region isconfigured to be actuated by a proximal handle and a distal handle. Insome embodiments, the guidewire coupler is configured such that thedevice is removably attachable to a proximal end region of a guidewiresuch that the tissue modification region can be pulled into position bypulling on the guidewire while the proximal end region of the guidewireis held stationary by the guidewire coupler with respect to the device.Alternatively, in some embodiments, the device includes a flexible guideat the distal end of the tissue modification device, wherein the guideis configured such that the tissue modification region can be pulledinto position by pulling on the guide.

In some embodiments, at least one cutting member comprises a cuttingwire, while in some embodiments, at least one cutting member comprises aGigli wire or an elongate wire having a helical cutting edge along thelength of the wire. In some embodiments, at least one cutting membercomprises an elongate cable having blade edges distributed along thelength of the cable.

In some embodiments, the device includes a spacer coupled to theelongate cutting members of the tissue modification region, wherein thespacer is sized and configured to temporarily hold the cutting members adistance from one another. In some embodiments, the spacer comprises anelongate, flexible, ribbon-shaped substrate and in some embodiments, thespacer includes a coupler toward the outer edge region of the spacer andconfigured to temporarily secure a cutting member to the outer edgeregion of the spacer. In some embodiments, the spacer is sized andconfigured to slide along the length of the elongate cutting members.

In some embodiments, the device further includes a plurality of flexiblyconnected rungs, wherein each rung extends at least partially across thewidth of the device. In some embodiments, the rungs are proximal anddistal to the tissue modification region of the device. In someembodiments, the device further includes a connector linking adjacentrungs. In some embodiments, the connector may include at least onecable, and in some embodiments, the cable may form the first elongatecutting member and the second elongate cutting member.

In general, a bimanually controlled tissue modification device forcutting tissue in a patient may include a pair of flexible, elongatecutting members extending along the elongate length of the device, and aspacer that may be positioned between the cutting members. In someembodiments, the spacer is sized and configured to operate in one of twomodes: a first mode, wherein the spacer is coupled to the cuttingmembers such that it holds a portion of each of the two cutting membersa distance from one another across the width of the device; and a secondmode, wherein at least a portion of the spacer is moved away from acutting member to allow the cutting members to cut further into tissue.In the first mode, the spacer(s) may be in the same plane as the cuttingmember, while in the second mode the spacer(s) may be displaced out ofthe plane.

In some embodiments, the elongate cutting members are substantiallyparallel to one another. In some embodiments, the spacer in the secondmode is positioned out of the plane of the cutting members. The devicemay include a guidewire coupler at the distal end region of the tissuemodification device. In some embodiments, the spacer in the second modeis positioned such that each of the cutting members can cut a depth intotissue that is greater than the thickness of the cutting members. Insome embodiments, the spacer further comprises a coupler configured tocouple the spacer to a cutting member while the spacer is in the firstmode. In some embodiments, the spacer transitions from the first mode tothe second mode as the cutting member cuts through the coupler. In someembodiments, the spacer transitions from the first mode to the secondmode as the coupler slides along the length of the elongate cuttingmember. Any appropriate number of spacers may be used. The same devicemay use different types or configurations of spacers.

In some embodiments, the coupler may be a deformable material sized andconfigured such that the spacer transitions from the first mode to thesecond mode as the deformable material deforms and a portion of thespacer moves with respect to the cutting member. In some embodiments,the device further includes a spring, wherein the spring is configuredto expand as the spacer transitions from the first mode to the secondmode. In some embodiments, the cutting members are sized and configuredto cut a first depth into the tissue while the spacer is in the firstmode and to cut a second, greater depth into the tissue while the spaceris in the second mode. In some embodiments, the cutting members areconfigured to be actuated by a proximal handle and a distal handle. Thecutting members may be reciprocated, for example, they may be pulleddistally by a distal handle and pulled proximally by a proximal handle.

In general, a method of modifying tissue may include the steps ofpassing an elongate, flexible tissue-modification device at leastpartially around a target tissue; moving a tissue-modification region ofthe device against the target tissue by pulling the tissue-modificationdevice from at least one end of the device; and cutting two discreteelongate troughs into the tissue with a pair of flexible elongatecutting members extending along the elongate length of the tissuemodification region. For example, the elongate cutting members may havea thickness (e.g., between about 0.01 cm and about 5 cm) and each of theelongate troughs may be cut to a depth that is greater than thethickness of the cutting members. In some embodiments, the elongatetroughs each have a depth greater than 1 cm. In some embodiments, theelongate troughs each have a depth greater than 2 cm. In someembodiments, the elongate troughs are substantially parallel to oneanother.

As mentioned, the troughs are typically discrete, and separated fromeach other. In some variations, the troughs may join or meet as thedevice continues to cut into the tissue (e.g., bone). The spacingbetween the troughs may be predetermined (e.g., 4 mm, 5 mm, 6 mm, 7 mm,8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18mm, etc.), which may correspond to the spacing between cutting elementson the cutting device.

In some embodiments, the method further includes the step of removingthe target tissue. The target tissue may comprise at least a portion ofa facet joint. In some embodiments, the step of passing thetissue-modification device at least partially around the target tissuecomprises passing a guidewire at least partially around the targettissue and pulling the flexible tissue-modification device around thetarget tissue using the guidewire. In some embodiments, the cutting stepincludes the steps of cutting the troughs to a first depth into thetissue with a pair of flexible elongate cutting members held a distancefrom one another with a spacer and cutting the troughs to a second,greater depth into the tissue with the pair of flexible elongate cuttingmembers.

The spacer may be moved with respect to the cutting members beforecutting the troughs to the second, greater depth. In some embodiments,the method includes the step of collecting cut tissue with the spacer asthe spacer moves away from the cutting members. The step of moving thetissue-modification device against tissue may comprises applying tensionto both the proximal end and the distal end of the tissue-modificationdevice to drive the tissue-modification device against the tissue eithersimultaneously or sequentially (e.g., reciprocating it).

In some embodiments, the method includes the step of cutting through acoupler with at least one of the cutting members while cutting thetroughs, wherein the coupler couples a spacer to the cutting member. Insome embodiments, the method includes the step of detaching at least oneof the cutting members from a coupler while cutting the troughs into thetissue, wherein the coupler couples a spacer to the cutting member. Insome embodiments, the cutting step further comprises reciprocating thetissue-modification region of the device against the target tissue bypulling the tissue modification region distally with a distal handle andby pulling the tissue modification region proximally with a proximalhandle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D illustrate elements that may be used for performing themethods described herein; some or all of these elements (the guidewireof FIG. 1A, neural localization device of FIG. 1C, flexible wire saw ofFIG. 1B, and parallel wire saw of FIG. 1D) may form a system for cuttingtissue.

FIGS. 2-3D show various embodiments of a cutting wire.

FIG. 4 illustrates a tissue modification device having a cutting wire.

FIG. 5 illustrates a method for cutting a lateral portion of a facet.

FIG. 6A illustrates a variation of a method for cutting the lateralportion of a facet.

FIG. 6B illustrates one step of a method for cutting a facet.

FIGS. 7-11 illustrate variations of a tissue modification device havinga pair of elongate cutting members.

FIGS. 12-14B illustrate tissue modification devices having shaped wires.

FIG. 15 shows another variation of a tissue modification device having apair of elongate cutting members.

FIGS. 16A-18D illustrate tissue modification devices having spacers.

FIGS. 19A-19B illustrate a variation of a rung of the tissuemodification device having a U-shaped cross section.

FIGS. 20A-20B illustrate another variation of a rung of the tissuemodification device having a U-shaped cross section.

FIGS. 21A-29 illustrate additional variations of the cutting devices andregions of cutting devices described herein.

FIG. 30A illustrates a cross-section through one variation of afacet-joint modifying device that includes two bone-sawing elements.

FIG. 30B illustrates a cross-section through one portion of the devicehaving a breakable spacer.

FIG. 30C shows a top view of one variation of a facet-joint modifyingdevice configured to perform a facetectomy.

FIGS. 31A-31E illustrate variations of joint treatment devices. In FIG.31A, the treatment device includes a front and a back articulatingsurface that can be drawn across the joint surfaces to roughen them;FIGS. 31B-31D show different cross-sections through joint treatmentdevices, and FIG. 31E illustrates another variation of a joint treatmentdevice. Any of these joint treatment devices may be facet jointtreatment devices.

FIG. 32 illustrates a facet joint including the superior and inferiorarticulating processes.

FIGS. 33-35 illustrates multiple variations of a tissue modificationdevice as described.

FIG. 36 illustrates one variation of an expanding mechanism asdescribed.

FIGS. 37-41D illustrate other variations of expanding mechanisms asdescribed.

FIG. 42 illustrates one variation of a tissue modification device havinga shield as described.

FIG. 43 illustrates another variation of a device and method formodifying tissue as described.

FIG. 44 illustrates a delivery device as described herein.

DETAILED DESCRIPTION OF THE INVENTION

Described herein are devices, systems and methods for cutting spinaltissue such as bone and/or soft tissue, and particularly spinal bone inthe dorsal column using a flexible cutting element that may be passedaround the bone. In some embodiments, these devices, methods and systemsmay be used to cut two substantially parallel cuts into tissue withoutrequiring the removal of the cutting element between cuts. The methods,devices and systems described herein may be used as part of a spinalsurgical procedure involving a complete or partial removal of spinalbone or joint, such as a laminectomy, laminotomy, fascetectomy,pediculectomy, etc.

FIGS. 1A-1D illustrate different elements that may be used as part of asystem for cutting bone as described. FIG. 1A shows a guidewire 100 thatis adapted to couple to the distal end of another device so that thedevice may be pulled into position using the guidewire. The distal end101 of the guidewire may be sharp, and the proximal end may include acoupling joint 102 (e.g., a ball or other enlarged region that can begripped by a coupling member).

FIG. 1B shows one variation of an elongate cutting member, such as acutting wire 103 having an abrasive surface for cutting tissue, such assoft tissue (e.g. ligament) and/or bone. Such saw wires (e.g.,traditional Gigli saws) may be adapted for use with a guidewire. Forexample, the distal end of the saw may include a guidewire coupler 104.In some variations the wire is thin or flattened. Any appropriate saw orcutting element may be used, including those that cut by reciprocationor by application of energy.

FIG. 1C illustrates one variation of a flexible ribbon-shaped neurallocalization device 105. The distal end 106 of the device issubstantially flat (not apparent from the figure) and has flat sideswith one or more electrodes 107 along the surface to stimulate a nerveor neural tissue, if nearby.

FIG. 1D illustrates another variation of a bone saw device having twoparallel cutting wires 108 that are separated by a predetermineddistance (e.g., 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm,13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, etc.). The distal end of thedevice may be configured for coupling to a guidewire 100. Alternatively,the device may have an integral flexible guide region 109 at the distalend of the device so that the device does not need any additionalguidewire/coupler. For example, flexible guide region 109 is shownhaving a curved shape to demonstrate that at least a portion of flexibleguide region 109 may be flexible. The distal portion is preferablyflexible in at least one direction, such that it may wrap around atarget tissue, while having sufficient column strength such that thedistal end may penetrate tissue without budding. In some embodiments,the distal end may have a sharp distal tip configured to penetrateand/or pierce tissue. In various embodiments, flexible guide region 109may have one or more of a round, ovoid, ellipsoid, flat, cambered flat,rectangular, square, triangular, symmetric or asymmetric cross-sectionalshape. Distal flexible guide region 109 may be tapered, to facilitateits passage into or through narrow spaces as well as through smallincisions on a patient's skin. Distal flexible guide region 109 may belong enough to extend through a first incision on a patient, betweentarget and non-target tissue, and out a second incision on a patient. Insome embodiments, the distal end may have a length greater than or equalto 3 inches such that it may extend from around the proximal end of thestimulation region to outside the patient where it may be grasped by auser and/or a distal handle. In some alternative embodiments, the distalend may have a length greater than or equal to 10 inches while in someother alternative embodiments, the distal end may have a length greaterthan or equal to 16 inches. Alternatively, distal flexible guide region109 may be long enough to extend through a first incision, between thetarget and non-target tissue, and to an anchoring location within thepatient.

The cutting wires 108 as described herein may be one of severalvariations of cutting wires. In some embodiments, the cutting wires mayhave an outer diameter that ranges from 5 to 50 thousandths of an inch,for example. A single wire saw may include a plurality of wires wrappedaround each other at differing pitches. As shown in FIG. 2, wire 202having a first diameter, may be wrapped around wire 201 having a seconddiameter. As shown, the first diameter may be less than the seconddiameter. FIG. 2 illustrates one example of a Gigli cutting wire.Alternatively, as shown in FIGS. 3A-3D, the cutting wire of the tissuemodification device can be one of several alternative embodiments. Forexample, as shown in FIG. 3A, the cutting wire may be a secondembodiment of a conventional Gigli wire. A Gigli wire is typically madeof a first wire having a first diameter wrapped around a second wirehaving a second diameter. Typically, the second diameter is larger thanthe first diameter, but alternatively, they may have substantially thesame diameter, as shown in FIG. 3A. In some embodiments, a first set offirst and second wires may be wrapped around a second set of first andsecond wires. Alternatively, as shown in FIG. 3B, the cutting wire mayinclude a single wire that is machined to include a helical or spiralcutting edge along the length of the wire. This wire may be machined bycutting a spiral or helical groove along the length of the wire. Asshown in FIGS. 3C and 3D, the cutting wires may be formed by windingbunches of wires. For example, as shown in cross section in FIG. 3D, thecutting wire may comprise a 3 by 3 construction. In this embodiment,three wires are first wrapped around one another to create a first bunchof wires. Then three sets of those three wire bunches are subsequentlywrapped around each other. As shown in cross section in FIG. 3C, ratherthan initially wrapping three wires together, 6 wires may be wrappedtogether to create a bunch of wires and then three sets of the 6 wirebunches may be wrapped together to form a 3 by 6 configuration. Each 6wire set may be formed as a 7 wire set might be formed, but leaving onewire position empty.

As shown in FIG. 4, a tissue modification device 400 includes a tissuemodification portion 401, a distal end 402, and a proximal end 403. Thetissue modification portion may include a wire saw configured to cutthrough bone and/or soft tissue. The distal end 402 may include aguidewire coupler. The proximal end 403 may be more rigid than theflexible tissue modification region 401. The proximal end may be coupledto a proximal handle used to grasp, position, and/or reciprocate thetissue modification device.

In operation, the devices described above may be used as part of asystem for cutting bone, as illustrated in FIGS. 5-6B. In this example,the facet is cut laterally, which may be used as part of a TLIFprocedure, for example. FIG. 5 shows an overview of this method. In thisexample, two cuts through the bone are made sequentially. To cut thefacet joint as desired for this procedure, a guidewire is firstpositioned partially around/against a superior articular process (SAP)500 that will be cut. The guidewire may be positioned using or moreprobes or cannula so that the guidewire enters laterally from a firstposition (A) passes through the foramen and around the SAP 500, andleaves the spine (and exits the patient) at a second position (A′). Oncethe guidewire is positioned, it may be used to pull in a neurallocalization device to confirm that a nerve (spinal nerve or nerve root)is not between the bone to be cut and the pathway of the guidewire.After confirmation that the nerve is not between the bone and thepathway, a cutting element (e.g., wire saw 1B) may be pulled intoposition so that both the distal and proximal ends of the wire saw exitthe patient and may be pulled upward (in the posterior direction) andreciprocated laterally to cut the SAP as indicated by the dashed line501 in FIG. 5.

Once the SAP has been cut by the saw, the saw may then be positioned forthe second cut, through the lamina. Optionally, before this cut is made,and before the wire saw is moved to this location, the lamina may beprepared by notching or biting away portion of the lamina 502 with aRongeur or other device (e.g. forming a laminotomy). For example, inFIG. 5, the dotted region shows an area 502 that may be bitten away toform a partial window into the lamina. Once that is done, the cuttingelement (wire saw) is moved in the cephalid direction (down in theorientation of FIG. 5), so that the ends of the wire extend in thecephalid direction (and across the central spinal axis). Thus, one endof the saw B is present in the notch or window formed in the lamina, andthe other end B′ moves along the foramen. If desired, the neurallocalization device may again be used to confirm that a nerve will notbe cut from this position, e.g., by retracting the guidewire proximally,removing the cutting element and attaching the neural localizationdevice. Finally, the cutting element may be reciprocated to cut throughthe pars region of the lamina along dotted line 503. Thereafter the cutaway portion of the bone may be removed, and other procedures performedas desired.

In the embodiments including two parallel wires, the facet or targettissue suture may be cut in a single step. For example, to perform aFacetectomy, the device may be deployed just cephalad of the caudalpedicle. The parallel wires may be held at the desired width, or thewires may be expanded to the desired width. The desired width may rangefrom 6 mm-15 mm, depending on the interbody device to be insertedbetween the vertebras, for example. In some variations, the cephaladwire may be expanded to the desired width. The device may then bereciprocated across the tissue to cut through and remove at least aportion of the width of the facet joint. The device may be reciprocatedby alternatively pulling a proximal end of the device (e.g. proximalhandle) and pulling a distal end of the device (e.g. a distal handleand/or or guidewire). While one end is pulled, the other end may also bepulled to maintain tension across the device.

FIGS. 6A and 6B illustrate alternative views of the steps describedabove. For example, FIG. 6A shows the steps of cutting through the SAP600 (dotted line 601), biting away/forming a window 602 in the lamina,moving the cutting element in the caudal direction (arrow 603) andcutting the pars (dotted line 604). FIG. 6B shows a cross-sectional viewthrough the spine indicating the cutting of the SAP. As shown, thecutting wire 600 is positioned through the foramen and around the SAP(not shown). The wire will be reciprocated and pulled in the directionof the arrows to cut through the SAP.

As mentioned above, in any of the facet joint procedures describedherein, all or a portion of the facet (e.g., the superior and/orinferior spinous processes) may be cut. For example, a procedure forfusing or preparing a facet joint may include a facetectomy,particularly for TLIF (Transforaminal Lumbar Interbody Fusion)procedures. The procedure may include a facet joint treatment devicethat is configured to saw through bone. For example, the device mayinclude one or more cable-type saws including a distal end that isconfigured to couple to the pull wire as described above. As mentioned,a probe or probes may be used to place the pull wire under the facetjoint. A facet joint modifying device may then be pulled in underbimanual control. Pulling the facet joint modifying device dorsally(e.g., by distal/proximal reciprocation) would result in the removal ofthe entire facet joint. This method may be faster than current methodswhich involve slow biting with Rongeur-type devices.

Tissue Modification Device Having Two Elongate Cutting Members

In some embodiments of the devices, systems and methods for cuttingtissue in a patient described herein, a tissue modification region of adevice includes a pair of flexible elongate cutting members extendingalong the length of the tissue modification region. Each elongatecutting member may be configured to cut a separate trough into tissue toa depth that is greater than the thickness of the cutting member.

In a first embodiment, the tissue modification device (e.g., bone saw)may include cutting edges directly coupled to a cable, as shown in FIG.7, the cable 701 may include cutting elements 703 such as beads, blades,wires, or other suitable cutting elements. In some embodiments, thecutting elements may be crimped onto the wire or attached by othersuitable methods. The cutting cables may cut tissue using an energy suchas heat or radio frequency energy. The energy may function to desiccateand/or shrink the tissue, rather than cutting it. As shown in FIG. 7, aportion of the device may include cutting cables 701, while a portion ofthe device includes spacers or rungs 702 threaded onto cables (with orwithout cutting edges on the spacers). The cutting cables and the cablesonto which the spacers are threaded may be the same or different cables.

As shown in FIG. 8, a tissue modification device 800 includes a tissuemodification portion 801, a distal end 802, and a proximal end 803. Thetissue modification portion may include two parallel wire saws 805configured to cut through bone and/or soft tissue. The distal end 802may include a guidewire coupler. The proximal end 803 may be more rigidthan the flexible tissue modification region 801. The proximal end maybe coupled to a proximal handle used to grasp, position, and/orreciprocate the tissue modification device. The proximal end 803 mayinclude a proximal connector element 804 that couples the proximal end803 to the parallel wire saws 805. In some embodiments, the tissuemodification portion 801 may include a single wire saw that is coupledat one end to the distal end, fed through the proximal connector element804, and coupled at a second end to the distal end. The cutting wire maybe configured to slide through the proximal connector element and to bemovable with respect to the proximal end 803. FIG. 9 shows the tissuemodification device positioned within a spine. As shown, the surfaces ofthe spine about which the device is positioned may be uneven. In someinstances, the device may not contact the surfaces of the spine in abalanced way, or may not be taut against the surface to be cut. As shownin FIGS. 9 and 10, the proximal connector element (labeled 904 and 1004,respectively) ensures that the cutting wire can slide through theconnector element and be repositioned such that both parallel portionsof the cutting wires can be taut against the tissue to be cut.

In an alternative embodiment, as shown in FIG. 11, the tissuemodification device may include a pulley 1101. The pulley is coupled tothe cutting wire 1102 and may be positioned at the proximal and/or thedistal end of the tissue modification device. The pulley may beconfigured to reposition the cutting wire such that both parallelportions of the cutting wires can be taut against the tissue to be cut.

As shown in FIG. 12, a tissue modification device 1200 includes a tissuemodification portion 1201, a distal end 1202, and a proximal end 1203.The tissue modification portion may include two parallel wire saws 1205configured to cut through bone and/or soft tissue. The distal end 1202may include a guidewire coupler. The guidewire coupler may be coupled toa guidewire (which may be coupled to a distal handle) and may be used tograsp, position, and/or reciprocate the tissue modification device. Theproximal end 1203 may be more rigid than the flexible tissuemodification region 1201. The proximal end may be coupled to a proximalhandle used to grasp, position, and/or reciprocate the tissuemodification device. The proximal end 1203 may include a proximalconnector element 1204A that couples the proximal end 1203 to theparallel wire saws and the distal end 1202 may include a distalconnector element 1204B that couples the distal end 1202 to the parallelwire saws. In some embodiments, the tissue modification portion 1201 mayinclude a single wire saw that is fed through the proximal connectorelement 1204A and the distal connector element 1204B. The cutting wiremay be configured to slide through the connector elements. As shown, theconnector elements are configured to hold the cutting wires apart fromone another. In some variations, the wires are held a distance apartthat is greater than the minimum desired width such that if someapproximation of the cutting wires 1205 does occur during positioningand/or reciprocation of the device (due to the geometry and/or oranatomy of the spine, for example), the wires will still be at least theminimum desired width apart. In some variations, the connector elementsare made from a flexible or shape memory material such as Nitinol. Inthis variation, if the connectors are compressed, such that the legportions of the connectors are brought closer to one another, theconnector legs will be biased apart and will return to their originalconfiguration.

In an alternative variation, as shown in FIGS. 13A and 13B, a tissuemodification device 1300 includes a tissue modification portion 1301, adistal end 1302, and a proximal end 1303. The tissue modificationportion may include two parallel wire saws configured to cut throughbone and/or soft tissue. The distal end 1302 may include a guidewirecoupler. The guidewire coupler may be coupled to a guidewire (which maybe coupled to a distal handle) and may be used to grasp, position,and/or reciprocate the tissue modification device. The proximal end 1303may be more rigid than the flexible tissue modification region 1301. Theproximal end may be coupled to a proximal handle used to grasp,position, and/or reciprocate the tissue modification device. In somevariations, the cutting wires are made from a flexible or shape memorymaterial such as Nitinol. As shown in FIG. 13A, the wires in theirequilibrium or biased configuration are held a first distance A apart.Distance A is wider than a minimum desired width. In this variation, ifthe cutting wires are compressed, such that the cutting wires arebrought closer to one another, the cutting wires will be biased apartand will return to their original, wider configuration. As described,the wires are held a distance apart that is greater than the minimumdesired width such that if some approximation does occur, the wires willstill be at least the minimum desired width apart. In operation, aguidewire may be coupled to distal end 1302 such that the tissuemodification device can be alternatively pulled by the guidewire and theproximal end of the device. As shown in FIG. 13B, as the device ispulled and reciprocated, it is possible that the wires will approximatetoward one another to a width B as the tissue modification portion 1301is elongated. Width B is preferably at least as wide as the minimumdesired width. In some variations, the device may further include alength limiting element 1304. As shown in FIG. 13A, the length limitingelement is flexible and not pulled taut. In FIG. 13B, as the device ispulled and reciprocated, the tissue modification portion 1301 iselongated only to the length of the length limiting element 1304. Thelength limiting element 1304 is configured such that the tissuemodification portion 1301 cannot be elongated such that width B is toosmall. Width B is preferably at least as wide as the minimum desiredwidth. Alternatively, in some variations width C is preferably at leastas wide as the minimum desired width.

In some embodiments, as shown in FIGS. 14A and 14B, the cutting wire mayhave a cross section that is configured to limit the flexibility in theorthogonal direction and therefore limit approximation of the wires. Asshown in FIG. 14B, the wider, substantially rectangular cross section isless susceptible to an orthogonal load as shown.

Tissue Modification Device Having a Spacer

In some embodiments, a tissue modification region of a cutting deviceincludes a pair of flexible elongate cutting members extending along thelength of the tissue modification region and also includes a spacer.Each elongate cutting member may be configured to cut a discrete troughinto tissue to a depth that is greater than the thickness of the cuttingmember. A spacer may generally span the width between the two cuttingmembers holding them some predetermined (or adjustable) distance apart.Since the spacers do not typically cut the tissue, they may beconfigured so that they do not substantially inhibit the cutting gwiresor edges from cutting the tissue. The spacer may be sized and configuredto operate in one of two modes. A first mode, in which the spacer iscoupled to the cutting members such that it holds a portion of each ofthe two cutting members a distance from one another, and a second mode,in which at least a portion of the spacer is moved away from a cuttingmember to allow the cutting members to cut further into tissue.

Referring again to FIG. 9, in some embodiments, the uneven or curvedsurfaces of the spine may cause the elongate cutting members 901 toapproximate at the apex of the curve and/or the anterior portion of thefacet joint, for example. If the wires approximate to a substantialdegree, the width of tissue cut and/or removed by the device may not beas wide as desired or required for the specific procedure. For example,if the wires are too close to one another, they may not be able to cutaround the facet joint and the entire facet joint may not be removed. Inthese cases, it may be advantageous to provide a tissue modificationdevice further including a spacer, as described in detail below.

FIG. 15 shows another variation of a parallel wire saw, in which theparallel wires 1500 and 1501 are held a minimum distance apart. Thus,although the device is flexible, it is desirable to have the distancebetween cutting wires (and thus the width of the bone chunk being cutaway) a predetermined length apart. In FIG. 15, one or more spacers 1502may hold the cutting wires apart. The spacers may be removed (e.g., bybreaking away or by separating from one side of the device) duringreciprocation, or they may be expandable (but not very compressible) sothat they may allow the cutting regions to bite into the bone whileexpanding.

FIGS. 16A-18D illustrate an alternative embodiment of a tissuemodification device 1600 having a pair of flexible elongate cuttingmembers 1601 and a spacer 1602. As shown in FIG. 16A, the tissuemodification device includes a distal end having a tissue modificationregion and a proximal end 1605 having, in some embodiments, a proximalhandle 1604. The distal tissue modification region includes the pair offlexible elongate cutting members 1601 and the spacer 1602. As shown, aguidewire coupler 1608 may be at the distal end of the tissuemodification device. The guidewire coupler may be configured to attachto a guidewire (e.g., the proximal end of a guidewire) so that thedevice can be manipulated (e.g. reciprocated), at least in part, bypulling on the guidewire after the guidewire has been secured to thedevice. As shown in FIG. 16A and in greater detail in FIG. 16B, thespacer 1602 may further include passive restraints 1609 coupled to theouter edges of the spacer. As shown, portions of these restraints arecoupled to cutting member 1601. These restraints may function to holdthe cutting wires toward the outer edges of the device and/or preventthe wires from approximating. As shown, the restraints may not run theentire length of the tissue modification region of the device. This maybe desirable such that a portion of the cutting wires 1601 are exposed.These exposed wires may provide cutting action during the initialreciprocations of the tissue modification device against the tissue. Asthe device is pulled back and forth (i.e. reciprocated) across thetissue, the exposed portions of the cutting wires 1601 will begin to cutthrough the bone and/or soft tissue. In some embodiments, the device ispulled “up” (toward the back of the patient) and against the tissuewhile the device is reciprocated across the tissue. Due to this upwardpressure, the cutting wires will begin to cut into the tissue and createtroughs into the tissue. As the initial troughs are formed in thetissue, and the cutting wires move deeper into the tissue, the cuttingwires will eventually detach from the restraints 1609. In someembodiments, the restraints are made from an elastic or otherwisedeformable material such that the upper lip (labeled 1707 in FIG. 17B)of the restraint can deform to allow the cutting wire to pull out of therestraint. Alternatively, the cutting wire may cut through or break offa portion (e.g., the upper lip) of the restraint.

Returning to FIG. 16A, the tissue modification device further includes aspring 1603. This spring may function to couple the shield 1602 to theproximal end 1605 of the tissue modification device. As the cuttingwires 1601 cut into the tissue, and the spacer 1602 moves away from thecutting wires, the spring 1603 will stretch and allow the proximal endof the spacer (labeled 1802 in FIGS. 18A-18C) to move toward the distalend of the device such that the distal end of the spacer may bend andmove away from the cutting wires 1601. Also, as shown in FIG. 16A, thetissue modification device may optionally include rungs 1607. Theserungs may thread over the wires that run the length of the device. Therungs may be positioned distal and/or proximal to the tissuemodification region of the device. In some embodiments, the spacer maybe connected to a rung(s) positioned distal to the tissue modificationregion.

FIGS. 17A and 17B illustrate in detail the passive restraint 1700 asdescribed above. As shown in FIG. 17A, the restraint includes an upperlip portion that couples to the cutting wire and temporarily holds thecutting wire in position, a distance from the other cutting wire. Theupper lip defines channel 1703 in which the cutting wire may betemporarily held. The restraint also includes a base portion that mayfunction to couple the restraint 1700 to the spacer of the tissuemodification device. As shown in FIG. 17B, the base portion 1702 of therestraint may define channel 1704. This channel may be sized andconfigured to receive the outer edge of the spacer. As shown in FIG.16B, the spacer may include two passive restraints, one coupled to eachedge of the spacer. In some embodiments, the restraint may extruded ormolded and then may be coupled to the spacer using adhesive, UV glue, orany other suitable coupling mechanism. Alternatively, the restraint maybe over-molded directly to the spacer.

FIGS. 18A-18D illustrate in detail the components of one embodiment ofthe tissue modification device. As shown in FIG. 18A, the tissuemodification device includes a spacer 1800 and at least one restraint1801 coupled to the outer edges of the spacer. The spacer includes adistal portion 1800 positioned within the tissue modification region ofthe device, adjacent to the cutting wires (labeled 1803 in FIGS.18B-18D), and a proximal portion 1802. In this embodiment, the distalend of the spacer 1800 is fixed to the distal end of the device and theproximal end 1802 is movably coupled to the proximal end of the devicevia a spring (labeled 1808 in FIGS. 18C and 18D). In some embodiments,the tissue modification region of the device may range from 1 cm toseveral inches long. The tissue modification region is preferably longenough to reciprocate against and cut through a facet joint, forexample. In some embodiments, a longer tissue modification region mayhave the added benefit of increased fatigue life of the cutting wiresdue to distributing the cutting load across longer wires. Alternatively,it is also desirable to design the tissue modification region such thatit is not so long that the cutting wires will approximate toward oneanother and adversely affect the effectiveness of the device.

As shown in FIG. 18B, the device further includes cutting wires 1803. Asshown, the cutting wires are positioned (at least initially) adjacent tothe restraints 1801. In this embodiment, the device may also includecables 1804 toward the distal end of the device and 1805 toward theproximal end of the device. As shown, in this embodiment, cutting wires1803 and cables 1804 and 1805 are all one continuous cable the runs fromthe proximal end to the distal end, through the guidewire coupler 1806at the distal end of the device, and back to the proximal end. In someembodiments, the cutting wire portion of the cable may include blades orother suitable cutting edges. In some embodiments, the cutting edges maybe sanded down or otherwise removed from the non-cutting portions of thecable (1804 and 1805). Alternatively, cables 1804 and 1805 may bedifferent cables or different materials coupled to cutting wires 1803.Furthermore, the single continuous cable may not wrap all the waythrough the distal end of the device. Alternatively, a separate cablemay loop through the distal end of the device (rungs 1809 in FIG. 18D)and the distal end may be coupled to the tissue modification region ofthe device with a separate coupling mechanism. Alternatively there maynot be a cable in the distal or proximal ends of the device.

As shown in FIG. 18C, the device may include a proximal end 1807 and aspring 1808. As described above, the spring 1808 may function to movablycouple the proximal end of the spacer 1802 to the proximal end of thedevice 1807 such that the spacer may move with respect to the cuttingwires 1803. As shown in FIG. 18D, in some embodiments, the device mayfurther include distal rungs 1809 and distal rungs 1810. These rungs mayfunction to add structure to the device while maintaining thinness andflexibility.

In some embodiments, as shown in FIG. 19A, the spacer may have a “U”shape (e.g. a rounded or a squared off U-shape). The spacer may includetwo leg portions 1901 and a base portion 1902. The leg portions may beperpendicular to the base portion, or may be configured in any othersuitable fashion. The leg portions may be substantially straight, or mayhave a curved configuration. The spacer may define an opening 1904through which a cable 1905 or other connector may be threaded. In someembodiments, the spacer may include a cutting edge 1903. The cuttingedge may be coupled to the leg portions of the spacer above the opening1904. As shown in FIG. 19B, the U-shaped spacers may function to allowthe legs of the spacers to pass through tissue 1908, such as ligamentand bone, as the cutting edges cut through the tissue, such that thebase portion of the spacer does not catch on the tissue or otherwiseobstruct the cutting of the tissue. As shown, a number of U-shapedspacers may be coupled to a cable to form a modification device. In someembodiments, secondary spacers 1906 may be coupled to the cable betweentwo adjacent U-shaped spacers. The secondary spacers 1906 may include acutting edge 1907.

In some embodiments, the leg portions may be flexible. As shown in FIGS.20A-B, the leg portion 2001 of the U-shaped spacer may be made from anexpandable or stretchable material, such that as the cutting edge 2002cuts through a tissue, the cutting edges and leg portions may extendfurther into the tissue (FIG. 20B), while the base portion 2002 remainson the surface of the tissue and does not catch on the tissue orotherwise obstruct the cutting of the tissue.

In some embodiments, the device further includes a sheath that coversthe cutting edges while the device is being introduced into a patient.Once the device has been introduced, the sheath may be removed. In someembodiments, the sheath further functions to remove the cut tissue.

In some embodiments, as shown in FIGS. 21A-21C, a spacer element 2101may be removably coupled to the cutting wires 2102 of the tissuemodification device. The spacer element may be coupled to the cuttingwires by a combination of sliding elements 2103 and/or breakawayelements 2104. The spacer may be flexible, rigid, or semi-rigid.Preferably, the spacer is rigid enough in the direction perpendicular tothe width of the spacer to prevent the cutting wires from approximatingcloser to one another than a desired width. For example, a desired widthmay be 8-15 mm, i.e. the width of an interbody device and or the widthor thickness of a facet joint. The spacer 2101 may be flexible in thelongitudinal direction and less flexible along its width. In someembodiments, as shown in FIGS. 21B and 21C, the spacer may be made of asilicone material or other suitable polymer. In use, the spacer mayinitially be coupled to the cutting wires by both sliding elements 2103toward the ends of the spacer and by breakaway elements 2104 toward thecenter of the spacer, as shown in FIGS. 21A and 21B. The breakawayelements may be slidably attached or fixed to the cutting wires. Thespacer is configured to maintain the distance between the cutting wireswhile the wires are positioned within the patient and during the initialreciprocations of the tissue modification device against the tissue. Asthe device is pulled back and forth (i.e. reciprocated) across thetissue, the exposed portions of the cutting wires 2102 will begin to cutthrough the bone and/or soft tissue. In some embodiments, the device ispulled “up” (toward the back of the patient) and against the tissuewhile the device is reciprocated across the tissue. Due to this upwardpressure, the cutting wires will begin to cut into the tissue and createtroughs into the tissue. As the cutting wires cut tissue, they will alsocut through the breakaway elements 2104, such that the spacer isreleased from the breakaway elements, as shown in FIG. 21C. Anadditional benefit to cutting troughs, as will be described throughout,is that by burying the cutting elements within the troughs created inthe tissue the neural and vascular structures (i.e. non-target tissue)will have limited exposure to the cutting wires. Alternatively, thebreakaway elements may release the cutting wires independently and arenot necessarily cut by the cutting wires. Once the spacer is released bythe breakaway elements, the spacer may be permitted to slide along thecutting wires at the sliding elements 2103. This feature is desirable inorder to allow the ends of the spacer to slide toward one another alongthe length of the wires such that the center of the spacer moves awayfrom the cutting wires, as shown in FIG. 21C. This allows the cuttingwires to cut deeper into the tissue without the spacer preventing orblocking the wires from cutting all the way through the tissue.Additionally, the spacer may be configured to catch or carry the cutand/or removed tissue in the space created between the spacer and thecutting wires.

FIGS. 22A-22B illustrate a side view of an alternative variation of aspacer between the cutting wires. As shown, the spacer 2201 is coupledto the cutting wires (only a single wire 2202 is shown) via a slidingcoupler 2203 and a fixed coupler 2204. Sliding coupler may be located adistance y from the fixed coupler. Alternatively, both couplers may beslidably connected to the cutting wire 2202. As the cutting wires arereciprocated across the tissue, the cutting wires begin to cut into thetissue creating troughs into the tissue. As the cutting wires enterdeeper into the tissue, the spacer rides along the outer surface of thetissue (substantially between and/or below the troughs being cut intothe tissue). The spacer must therefore separate from the cutting wiressuch that the cutting wires can continue to cut deeper troughs and moveinto the tissue without being restricted by the spacer. The sliding end2203 of the spacer slides toward the fixed end 2204 of the spacer suchthat distance Y is reduced to Y′ and such that distance X between thecenter of the spacer and the cutting wire increases as shown in FIG.22B.

As shown in FIGS. 23A-23C, a rigid (or semi-rigid) spacer 2301 may becoupled to the cutting wires 2304 via at least one flexible portion2302. The flexible portion 2302 may be fixed to the cutting wire bycoupling element 2303. Coupling element 2303 may fix the flexibleportion 2302 to the cutting wire 2304, but may alternatively slidablycouple the flexible portion to the cutting wires. As described above,the rigid spacer is configured to hold the cutting wires at a desiredwidth. The spacer will hold the wires apart while the device ispositioned and while the initial cutting occurs. As shown in crosssectional view and axial view in FIGS. 23B and 23C respectively, as thecutting wires 2304 cut deeper into bone 2305 (or other tissue), thetissue (specifically tissue section 2307) prevents the spacer fromentering into troughs 2306 formed by the cutting wires 2304. The spacertherefore “pops” off of and/or away from the cutting wires 2304, therebystretching flexible portion 2302. As shown in FIG. 23C, the spacerremains exterior to the target tissue as the cutting wires cut deeperinto the target tissue. For example, tissue section 2307 may include afacet joint. As the cutting wires are reciprocated and moved up throughthe tissue, eventually the section 2307 of tissue will be completely cutaway from the remainder of the tissue 2305.

FIG. 24A illustrates a top view of a tissue modification device, andFIG. 24B illustrates a rear view of the same tissue modification device.The device shown may be inserted into a spine and around a facet joint,for example, such that the top portion of the device (FIG. 24A) facestarget tissue (e.g. a facet joint) and the bottom portion of the device(FIG. 24B) faces non target tissue (e.g. neural or vascular tissue). Asshown in FIGS. 24A and 24B, a rigid (or semi-rigid) spacer 2401 may becoupled to the cutting wires 2404 via at least one flexible portion2402. As shown, the flexible portion may extend the length of the tissuemodification device such that the spacer 2401 may be coupled to the backside of the flexible portion, as shown in FIG. 24B. The flexibleportion, in this variation, is fixed to the tissue modification deviceat positions 2403. As described above, the spacer is configured to holdthe cutting wires at a desired width. The spacer will hold the wiresapart while the device is positioned and while the initial cuttingoccurs. In this variation, the spacer 2401 is coupled to the cuttingwires 2404 by breakaway elements 2415. As described above, the breakawayelements may be slidably attached or fixed to the cutting wires. As thedevice is pulled back and forth (i.e., reciprocated) across the tissue,the cutting wires 2404 will begin to cut through bone and/or softtissue. In some embodiments, the device is pulled “up” (top side of thedevice toward the back of the patient) and against the tissue while thedevice is reciprocated across the tissue. Due to this upward pressure,the cutting wires will begin to cut into the tissue and create troughsinto the tissue. As the cutting wires cut tissue, they will also cutthrough the breakaway elements 2415, such that the spacer is releasedfrom the breakaway elements.

In an alternative variation, as shown in FIG. 25, the spacer 2501 mayinclude only a single flexible portion 2502. In this variation, thespacer may be coupled to the cutting wires 2504 at a first end 2508while the flexible portion is coupled to the cutting wires 2504 at asecond end 2509. As shown, the spacer 2501 is preferably rigid in afirst plane (across the width of the device, i.e. into the page) suchthat it will prevent approximation of the cutting wires. The spacer maybe flexible in a second plane (along the length of the device) and/or ina third plane (across the thickness of the device, i.e. up and down withrespect to the FIG).

In another alternative embodiment, the rigid or semi-rigid spacer 2601,as shown in FIGS. 26A-26C is removably coupled to the cutting wires2604. As shown in cross sectional view in FIG. 26A, as the cutting wires2604 cut deeper into bone 2605 (or other tissue), the tissue 2605prevents the spacer from entering into troughs 2606 formed by thecutting wires 2604. The spacer therefore “pops” off of and away from thecutting wires 2604′ that are within the tissue 2605. As shown in FIG.26A, the spacer 2601 remains exterior to the target tissue as thecutting wires 2604′ cut deeper into the target tissue. In somevariations, the cutting wires 2604 may be able to slide within thetroughs 2612 of the spacer. In this variation, the spacer may be static(i.e. not reciprocating) while the wires are reciprocated. The materialof the spacer may be a molded polymer, or alternatively an extrudedpolymer. The elastic nature of the material would facilitate bothloading and release of the cutting wires.

In yet another alternative variation, as shown in cross section in FIG.27A, rather than “popping” off of the cutting wires 2704, the spacer2701 is configured to slide off of the cutting wires. In somevariations, the spacer may not be removed completely from the tissuemodification device, but may be removed from a portion of the cuttingwires to allow at least a portion of cutting wires 2704 to cut intoand/or through tissue. In some embodiments, the spacer may bunch andfold up along the cutting wires rather than sliding completely away. Asshown in FIG. 27A, the spacer may further include coupling elements 2710that are configured to removably couple the spacer to the cutting wires2704. Coupling element 2710 may be crimped, welded or coupled to thecutting wire in any suitable fashion. In some variations, the cuttingwires may be replaced by non cutting cables and the coupling elements2710 may include cutting edges (not shown).

FIG. 27B illustrates (in cross section) an alternative embodiment of aspacer 2705. For example, as shown in FIG. 27B, the spacer may includecutting ridges 2707. These cutting ridges may extend such that they havea height that is greater than the diameter of the cutting wires 2706.The cutting ridges may function to hold the cutting wires a distanceapart from one another and prevent the cutting wires 2706 fromapproximating. The spacer is configured to maintain the distance betweenthe cutting wires while the wires are positioned within the patient andduring the initial reciprocations of the tissue modification deviceagainst the tissue. As the device is pulled back and forth (i.e.reciprocated) across the tissue, the cutting ridges will begin to cutthrough the bone and/or soft tissue. In some embodiments, the device ispulled “up” (toward the back of the patient) and against the tissuewhile the device is reciprocated across the tissue. Due to this upwardpressure, the cutting ridges will begin to cut into the tissue andcreate troughs into the tissue. The cutting ridges may be positioned atdiscrete locations along the length of the device. Therefore, as theinitial troughs are formed, eventually, the cutting wires may fall intothe troughs and continue cutting deeper troughs as the spacer moved awayfrom the cutting wires.

In any of the variations described above, the spacer may additionally beconfigured to function as a shield that functions to prevent non-targettissue such as nerves or arteries from damage while the tissuemodification device is used to cut and/or modify tissue within apatient. In some embodiments, the spacer and/or shield may includeelectrodes and may be configured to detect neural structures asdescribed in conjunction with FIG. 1C. Alternatively or additionally,the spacer and/or shield may be configured to deliver drugs, haemostaticagents, or other suitable agents. In some embodiments, the spacer and/orshield may be tapered. For example, the distal end may be narrower thanthe proximal end such that the user may pull the device into position.The tapered nature of the spacer ensures that the surgeon can pull thedevice in as far as is desired before beginning reciprocation, therebyoptimally separating the wires before pulling them into the tissue. Forexample, to perform a pedicle to pedicle Facetectomy, the user may pullthe device in until each side of the device is against a pedicle.

In some embodiments, the device may be configured to aid in thereleasing of adhesions. For example, the facet capsule or bone may beadherent to dura, neural or vascular elements in the foramen. Tofacilitate the surgeons' or users' ability to release these potentialadhesions and ensure that the facet is free from these vulnerabletissues, one of the following devices described may be helpful.

In some embodiments, the spacer is a slider element 2801 as shown inFIG. 28. Slider element 2801 is coupled to cable 2811 which may becoupled to an actuator (not shown) located on the proximal portion 2812of the device, in some instances, at or near a proximal handle. As thetissue modification device 2800 is inserted into and positioned within apatient, slider is positioned toward the center of the tissuemodification portion of the device, e.g. toward the center of thecutting wires 2804. As shown, the slider is positioned a distance A fromthe distal end of the cutting wires and a distance B from the proximalend of the cutting wires. A user may position the distal portion(distance A) around the target tissue. Slider 2801 may limit the initialstroke length of the reciprocations to substantially the length A. Ashorter stroke length may provide greater control and/or less of apropensity for the wires to approximate during reciprocation. Once auser has initiated cutting with the cutting wires 2804 and/or once thecutting wires have formed initial troughs in the target tissue, theslider may be slid proximally to increase the stroke length from lengthA to a length equal to or less B.

As shown in FIG. 29, in an alternative variation, the slider 2901 mayhave a pronged configuration. The slider in this configuration is rigid,at least across the width of the device, to prevent the wires 2904 fromapproximating during reciprocation. The slider may be pronged such thatthe pronged portions may be inserted into the troughs created by thecutting wires. As described above, the slider may be coupled to anactuator.

FIG. 30A illustrates a cross-section through one variation of afacet-joint modifying device that includes two bone-sawing elements3002, 3002′. The two saw elements (which may be cables or surfacesincluding blades) may be separated by a spacer 3005. FIG. 30C shows atop view of one variation of a facet-joint modifying device configuredto perform a facetectomy. The distal end of the device is configured tocouple with the pull wire, as described above. The tissue-contactingportion of the device may include two parallel cutting surfaces (whichmay be cables) 3002, 3002′ that are separated from each other. These twoseparate cutting surfaces may allow two cuts to be made through thefacet joint simultaneously, permitting removal of a portion of the facetjoint. This version of the facet-joint modifying device may also includeone or more spacers 3005. Spacers may prevent the cutting surfaces fromspreading or contracting towards each other, particularly if the cuttingsurfaces are cables. In some variations these spacers may be removableor separating, so that as the facet joint modifying device cuts thefacet joint, pressure applied as that device is reciprocated against thebone may cause separation, breaking, or removal of the spacer. FIG. 30Billustrates a cross-section through one portion of the device having abreakable (e.g., frangible) spacer 3005.

Tissue Modification Device Having Single Tissue-Modifying Surface

Other facet joint modifying devices (including those shown in FIGS.31A-31E) may include a single tissue-modifying surface, and thus doesnot need a spacer. In one variation of a method for performing afacetectomy, a cannulated probe for guiding a guidewire/pull wire isfirst inserted in and/or around the joint. FIG. 32A illustrates a facetjoint 3205 including the superior articulating process (SAP) andinferior articulating process (IAP) between the lower 3209 and upper3207 vertebra. A guidewire/pull wire may be threaded through, around, oradjacent to the facet joint as indicated generally by the line 3203. Insome variations, the pathway through the facet joint passes over the topof the superior articulating process (SAP). In some variations, thepathway through the facet joint passes under the SAP giving access tothe tip of the SAP. Placement of the guidewire around or through thefacet joint may be aided by distraction of the spinous process. Thus, insome variations, the spinous process may be distracted before performingthe procedure.

Once the probe has been used to position the guidewire, it may beremoved. As illustrated above, the probe may include one or a pluralityof (concentric) cannula including cannulas having different curvaturesso that the guidewire may be directed around the joint and pointedtoward the appropriate exit site. The guidewire or pull wire may then bepushed through the cannula and out of the patient. A distal handle maythen be attached to the distal end of the guidewire to aid inmanipulating the guidewire/pull wire from the distal end.

Next, a treatment device may be pulled into position in or around thejoint by coupling the distal end (or end region) of the joint treatmentdevice to the proximal end of the guidewire/pull wire. In somevariations the treatment device includes one or more surfaces that areconfigured to abrade, scratch or otherwise remove bone to perform afacetectomy. For example, FIGS. 31A-31E illustrate variations of atreatment device. In FIG. 31A, the treatment device includes a front anda back articulating surface that can be drawn across the joint surfacesto roughen them and/or remove bone from the joint. In this example, thedistal end of the device includes an attachment/connector site for theguidewire. The proximal end also includes an elongate member and mayhave a proximal handle. In some variations the roughening surface isexpandable, so that it may be pulled into the joint in a collapsed orcondensed form (protecting non-target tissue), and once in the joint itcan be expanded to the treatment form. For example, the device may beinflatable; inflation may expand the device so that the contactsurface(s) can push against the joint surface(s). Once in position, thedevice can be moved bimanually within or around the joint to scrape orotherwise modify the joint to remove bone, by pulling distally andproximally (e.g., back and forth).

FIGS. 31B-31D illustrate alternative cross-sections for the jointtreatment devices described. For example, in FIG. 31B, the device issubstantially flat, having an upper and lower surface. As mentioned,this device may be inflatable/expandable to increase (or decrease) thespacing between the upper and lower surfaces, or to “stiffen” theimplant once it is expanded. FIG. 31C shows a device having an ovalcross-section, and FIG. 31D shows a device having a round cross-section.In all of these variations the devices include ‘teeth’ or protrusionsthat are configured to remove or modify bone or other tissue. In somevariations the devices are configure to abrade, cut, and/or removecartilage in the joint. In some variations the device is configured toabrade cartilage without substantially cutting or removing bone. In somevariations the device surface is configured to abrade cut and/or removebone from the joint and or remove the joint all together.

The device may be actuated by moving it backwards and forwards(proximally and distally), by bimanual reciprocation. In somevariations, such as that shown in FIG. 31E, for example, the device mayalso or alternatively be articulated by rotating it axially once it isin position in the joint or around the joint.

Expandable Tissue Modification Devices and Methods

Some variations of the tissue modification devices described hereininclude an elongate, flexible element having a first width and a secondwidth and a tissue modification element coupled to the flexible element.The flexible element may include an expanding mechanism that expands atleast a portion of the flexible element from the first width to thesecond width. Each of these features is described and illustrated ingreater detail below.

As shown in FIG. 33, in some embodiments, the tissue modification deviceincludes an elongate, flexible element 3301 having a first width (notshown) and a second width (shown). The flexible element has an axiallength, a width (first and second) and a thickness. As shown, the axiallength is greater than the width, and the width is greater than thethickness. In some embodiments, the first width may be substantiallyequal to or less than the thickness and the second width may be greaterthan the thickness. The first width is generally smaller than the secondwidth. The flexible element is preferably sized and configured such thatit may be inserted into a patient in the first width, and then expandedto the second width in order to modify target tissue. For example, theflexible element may be expanded to the second width in order to wraparound a facet joint such that element 3302 is on a first side of afacet joint (such as the superior articular process (SAP)) and element3303 is on a second side of the facet joint (such as the inferiorarticular process (IAP)) In some variations, the device will modify orremove a width of target tissue that is substantially equal to orgreater than the second width of the flexible element. In one specificexample, the first width may be 2-15 mm such that the device may fitwithin an interlaminar window of a patient's spine. The second width maybe 5-20 mm such that the device may modify a width of tissue that is5-20 mm wide such as the facet joint of a patient's spine. In somevariations, the second width of the device may range from 8 to 15 mmsuch that the user may then insert an inter body device, such as a cage,through the opening created to the space between adjacent vertebralbodies. The flexible element may be adjustable to a plurality of secondwidths. For example, the flexible element may be inserted into a patientat a first width and then advanced such that it is adjacent to a targettissue, around a facet joint for example. The flexible element may thenbe expanded until it contacts an adjacent pedicle or other suitableanatomy and can no longer expand.

The flexible element 3301 may include two flexible elongate cables 3302and 3303 that are expandable from the first width to the second width.The wires may be configured such that for the first width of theflexible element, the wires are adjacent to one another and/orsubstantially touching along their length. The wires may then beseparated from one another, as shown in FIG. 33, such that the flexibleelement has a second width. The cables may extend substantially adjacentto each other from the proximal end of the device to the distal end ofthe device. At least a portion of the cable is flexible. Any appropriatecable may be used, including metal or polymeric cables. Cables may besingle-filament or formed of multiple filaments. The portion of thecable towards the distal end of the device, as shown in this example,may be hinged or otherwise coupled to a coupling element 3304. Couplingelement 3304 may be configured to receive an end of a guidewire or pullwire, such that flexible element may be pulled and/or positioned by thepull wire.

In FIG. 33, the flexible element 3301 of the device is joined to theproximal end of the device 3305, which may be less flexible, and mayinclude a handle or an attachment region for a handle. This interfacebetween the flexible cables and the proximal end and/or handle may be ajoint or hinge, or any other suitable coupling mechanism. The proximaljoint near the proximal end may be a ball joint, in some embodiments,which allows the rotation of the handle and/or proximal portion of thedevice with respect to the tissue modification region and/or flexibleelement of the device. Thus, the proximal handle may be rotated alongthe long axis of the tissue modification device, but will notsubstantially torque the tissue modification region of the device. Thevariation shown in FIG. 33 may also include a proximal connecting regionnear the proximal end 3305 of the device to which a handle is attached.This connecting region may be relatively stiff (or inflexible), or itmay also be flexible.

In some embodiments, as described below, the flexible element maycomprise a balloon or other suitable flexible element. In someembodiments, as shown in FIG. 34, the flexible element may comprise aloop of cable, rather than two separate cables. Cable loop 3401 may beexpandable from the first width to the second width. The cable loop maybe configured such that for the first width of the flexible element, twoside portions of the loop are adjacent to one another and/orsubstantially touching along their length. The two side portions of theloop may then be separated from one another, as shown in FIG. 34, suchthat the flexible element has a second width. The device may furtherinclude a pulley 3402 or other suitable gear or wheel, as shown in FIG.34, about which the cable loop may be wound. The pulley may function toexpand the cable loop from the first width to the second width, and ormay function to aid in the reciprocation of the cable loop for cuttingtissue as described below.

The tissue modification device includes a tissue modification elementcoupled to the flexible element. In a first embodiment, the flexibleelement includes at least one wire that is configured to cut tissue orotherwise modify tissue. The wire may be textured or coated such that itis adapted to cut tissue. As shown in FIG. 33, the device furtherincludes at least one cutting edge 3306 coupled to at least a portion ofthe flexible element 3301. In some embodiments, the cutting edge iscrimped onto the cable. The tissue modification device may includecutting edges directly coupled to a cable, it may include ferrules orbeads threaded onto the cables onto which a cutting edge is fixed orintegrated, or the device may include any other suitable cutting edgescoupled to the flexible element in any suitable fashion. The flexibleelement may include cutting elements such as beads, blades, wires, orother suitable cutting elements. As shown in FIG. 33, a portion of thedevice may include cutting cables, while a portion of the deviceincludes rungs threaded onto cables (with or without cutting edges onthe rungs). The tissue modification device may modify or cut tissue bymoving the modification elements against the target tissue. In somevariations, the device is reciprocated against the target tissue. In analternative embodiment, a first cable of the flexible element is movedagainst the target tissue in a first direction, and a second cable ismoved against the target tissue in a second direction, and then eachcable is reciprocated against the target tissue. Alternatively, in thecase of the flexible element comprising a loop of cable, the loop mayrotate or be driven against the target tissue, as shown in FIG. 34.

In an alternative embodiment, the tissue modification element may modifytissue using an energy such as heat or radio frequency energy. Theenergy may function to desiccate and/or shrink the tissue.Alternatively, the energy may function to cut the tissue. As shown inFIG. 35, the flexible element may further include a cutting loop 3500that functions to cut, desiccate, and/or shrink the target tissue. Insome embodiments, the flexible element is coupled to a heating elementor other energy source.

In some embodiments, the tissue modification device includes anexpanding mechanism that expands at least a portion of the flexibleelement from the first width to the second width. In a first embodiment,as shown in FIG. 36, the flexible element comprises two wires 3601 and3602 expandable from a first width (A) to a second width (B). In someembodiments, the expanding mechanism further functions to hold theflexible elements in position, i.e. hold them a distance apart (thesecond width) and prevent them from approximating, particularly whilemodifying tissue with the device.

In a first variation, as shown in FIG. 36, the expanding mechanism 3603is coupled between the two wires 3601 and 3602 and separates the wiresfrom a first width to a second width as the expanding mechanism is movedalong the length of the wires. The expanding mechanism may be triangularshaped or otherwise configured to function in a manner similar to azipper or ZIP-LOCK bag sliding mechanism. Alternatively, as shown inFIG. 37, the expanding element may be an expander rod 3703. The rod maybe inserted between the two wires or cables once the wires are in place(i.e. inserted into a patient and/or adjacent to target tissue), and maybe sized and configured to expand the flexible element from a firstwidth (A) to a second width (B).

In an alternative embodiment, as shown in FIG. 38, the expandingmechanism comprises a first element 3801 coupled to two wires 3802 and3803 at a first location and a second element 3804 coupled to the twowires at a second, distal location. The device may be inserted into apatient while the wires are a first width apart, and then by moving thefirst element 3801 toward the second element 3804, as shown in FIG. 38,the wires expand from a first width to a second width.

As shown in FIGS. 39 and 40, the expanding mechanism may comprise aframe 3900, expandable from a first width (not shown) to a second width.The frame may be a shape memory material such as Nitinol or any othershape memory, shape changing, or super elastic material. The frame maycomprise at least two frame portions (such as wires 3901 and 3902) thatare expandable from a first width to a second width. In a firstembodiment, as shown in FIG. 39, the frame may further include a mesh3903 or other material coupled to the frame between the frame portions.The mesh may function to capture and/or remove cut or modified targettissue, such as a facet joint. In some embodiments, the frame may notcompletely encircle the mesh material, for example, the frame maycomprise a distal end and a proximal end, each with an expandable forkstructure.

As shown in FIG. 40, the frame may further include a sleeve 4001 coupledto the frame 4000. The sleeve may have a width substantially equal tothe first width of the flexible element, such that the frame may beinserted into the sleeve and held at a first width. The sleeve may thenbe pulled back (shown in FIG. 40 in the pulled back position) to allowthe frame to separate. When removing the device after modifying tissue,the frame in some embodiments, may be configured to grab the modifiedtarget tissue 4002 as the frame retracts (shown by arrows 4003) and pullthe tissue back with the frame into the sleeve 4001 for easy removal ofthe tissue.

As shown in FIGS. 41A and 41B, in some embodiments, the expandingmechanism is a balloon 4100. The device in this configuration may havecutting blades 4101 coupled to the side portions of the balloon suchthat the blades may cut a width of tissue substantially equal to thewidth of the balloon in its inflated or expanded configuration. In thisembodiment, the balloon may further include hook 4102 configured tocapture soft tissue, such as ligament, for example.

As shown in FIGS. 41C and 41D, the expanding mechanism may be actuator4103 (FIG. 41B) or actuator 4104 (FIG. 41C). In a first variation, asshown in FIG. 41C, the actuator 4103 is a spring or piston that expandsand contracts to move the flexible element 4105 from a first width to asecond width (shown). In a second variation, as shown in FIG. 41D, theactuator is wire 4104 made from a shape memory material such as Nitinolor any other shape memory, shape changing, or super elastic material.The wire may be coupled to the flexible element 4105 as shown and isexpandable such that it moves the flexible element from a first width toa second width (shown).

As shown in FIG. 42, the device may include a shield 4200 coupled to theflexible element. The shield may be coupled to the flexible element 4201such that while the flexible element is adjacent to the target tissue,the shield protects the adjacent non-target tissue, such as neuraltissue, and/or may collect the tissue cut and/or modified by the device.In some embodiments, the flexible element functions to slide distallyand proximally within or over a substantially stationary shield. In someembodiments, the shield may function to contact and/or engage with andremove tissue (for example, a facet joint) cut and/or modified by thedevice. In some embodiments, as shown in FIG. 42, the flexible elementcomprises two wires 4202 and 4203 coupled to a shield and held adistance apart from one another. The shield is coupled adjacent to thebottom surface of the flexible element and is sized and configured tomaintain the width of the flexible element by preventing the cables fromapproximating toward one another while modifying tissue.

In some embodiments, the device may include a tracking element. Forexample, a tracking element may be disposed in the distal end of thedevice, such that the tip of the device may be tracked as it is insertedinto a patient and/or moved within the patient. Alternatively, thedevice may include multiple tracking elements disposed along the lengthof the device, or multiple tracking elements disposed along a portion ofthe length of the device (for example along the cutting region of thedevice). In some embodiments, the tracking element is a material that isdetectable by an imaging system. Some examples of suitable trackingelements include echogenic materials or substances (i.e. configured toform an echogenic surface) detectable by an ultrasound system, andradio-opaque materials detectable by a radiograph system, such as afluoroscope. Alternatively, the tracking element may be configured to bedetectable by an MRI or Infrared system. In some embodiments thetracking element is preferably a coil configured to be detected by anelectromagnetic tracking or navigation system. For example, the devicesdescribed herein may incorporate a tracking system such as the AXIEM™Electromagnetic Tracking Technology, e.g., the StealthStation® AXIEM™(Medtronic Navigation, Louisville, Colo. USA). In some embodiments, thedevice is configured to generate an electromagnetic field around apatient's target anatomy that can be tracked to triangulate thepositioning of devices having tracking elements.

As mentioned above, any of the device described herein may include aguidewire coupler. A guidewire coupler is configured to attach to aguidewire (e.g., one end of a guidewire) so that the device can bemanipulated, at least in part, by pulling on the guidewire after theguidewire has been secured to the device. For example, in somevariations a guidewire may be inserted into the body from a firstlocation outside of the body, then passed around the target tissue(e.g., around a spinal foramen) and out of the body from a secondposition. The distal end of the guidewire may then be coupled to thetissue modification device (such as the one shown in FIG. 33) and pulledthrough the body until the tissue modifying region of the device, e.g.,the portion of the device including tissue modification elements 3306,is positioned opposite the target tissue. In some variations theguidewire used includes a tip region that is enlarged and may engage theguidewire coupler. For example, the guidewire may have a proximal endwith a flange or ball. This enlarged region may be configured to fitinto an opening on the guidewire coupler so that the guidewire can bepulled distally from outside of the patient. In some variations thedistal end of the device may be completely withdrawn, so that it can begrasped and manipulated. In other variations, the distal end of thetissue-modification device remains coupled to the guidewire, and theguidewire may be grasped to manipulate the distal end of thetissue-modification device. A handle may be attached to the guidewire.As mentioned, in operation, the device is urged against the targettissue and may be moved in the proximal/distal direction to modify(e.g., cut) the target tissue. For example, both the proximal and distalends of the tissue-modification device may be pulled to urge the deviceagainst the target tissue, and may each be alternately pulled to agreater degree than the other handle to slide the device over the targettissue, allowing the cutting edges to cut and modify the target tissue.

For example, a guidewire coupler may include an opening and/or channelto receive an enlarged or necked region at the proximal end of theguidewire. This configuration may be similar to the “trailer hitch”configuration described in many of the references previouslyincorporated by reference.

The methods for modifying tissue described herein typically include oneor more of the following steps: inserting an elongate, flexible elementhaving a first width; advancing the flexible element until a portion ofthe flexible element is adjacent to a target tissue; expanding at leastthe portion the flexible element adjacent to the target tissue to asecond width; and modifying the target tissue with the flexible element.A method for modifying tissue may include one or more of these steps inany combination. Each of these steps is described and illustrated ingreater detail below.

The inserting functions to bring the device into position. The insertingstep may further include inserting the device into a patient, and morespecifically into the spine of a patient, for example. In somevariations, the device may be inserted through an interlaminar window ofa patient's spine. In this variation, the flexible element is preferablyconfigured in the first width. The first width may be equal to orsmaller than the space defined by two adjacent amina (i.e. theinterlaminar window). Once inserted, the device may be advanced intoposition. The device may be moved until it is adjacent to the targettissue. In some embodiments, the advancing step further includes thesteps of passing a guidewire at least partially around the target tissueand pulling the device around the target tissue using the guidewire,such that the flexible elements and/or cutting element are adjacent tothe target tissue. In some embodiments, the guidewire is coupled to theguidewire coupler at the distal portion of the device. The inserting andadvancing steps may be performed while the flexible element isconfigured in the first width. This allows the device to be smaller andmore maneuverable such that it may fit through and around tightanatomical spaces and locations.

Once the device is positioned correctly within the patient, it may bedesirable to expand the flexible element from the first width to thesecond width. The expanded width (second width) is wider than the firstwidth, and allows the cutting elements coupled to the flexible elementto modify a wider and/or larger portion or area of target tissue. Insome embodiments, the second width may be substantially equal to (orslightly smaller than) the width of a facet joint, the width of theneural foramen of a patient's spine, and/or the width of an interbodyfusion device. In some embodiments, the second width may besubstantially equal to (or slightly smaller than) the distance from afirst pedicle to an adjacent pedicle. Once the device is expanded, thewider device may be used to modify target tissue.

In some embodiments, the modifying step further includes moving theflexible element across the target tissue. The flexible element may bemoved through or over the target tissue. The flexible element may alsobe reciprocated or moved back and forth across the target tissue inorder to modify an area of target tissue. The modification elements maybe reciprocated between a distal position and a proximal position. Thedevice may be reciprocated by applying tension to both the proximal endand the distal end of the device to drive the flexible element and/ortissue modification elements against the target tissue.

In some embodiments, modifying target tissue may include cutting a widthof tissue, such as a facet joint, having a width substantially equal tothe second width of the flexible element. As shown in FIG. 43, methodsfor modifying tissue described may alternatively include one or more ofthe following steps: inserting a first elongate, flexible element 4300into the patient at a first location; advancing the first flexibleelement until a portion of the flexible element is adjacent to a targettissue; inserting a second elongate, flexible element 4301 into thepatient at the first location, a distance from the first flexibleelement; and modifying the target tissue with the flexible elements. Amethod for modifying tissue may include one or more of these steps inany combination. Each of these steps is described and illustrated ingreater detail below.

In some embodiments, the inserting a second flexible element stepfurther includes inserting a second flexible element a distance from thefirst flexible element, wherein the distance is substantially equal tothe width of the facet joint. Alternatively, the inserting a secondflexible element step may further include inserting a second flexibleelement a distance from the first flexible element, wherein the distanceis substantially equal to the width of an interbody fusion device. Onceinserted, the two flexible elements may be coupled to a distal handle4302 and/or a proximal handle 4303. The method may further include thesteps of coupling the distal end of the first flexible element to adistal handle and then coupling the distal end of the second flexibleelement to the distal handle.

These steps have the benefit in that the single flexible element may beinserted and easily maneuvered independently through tight anatomicalsites and locations. By then inserting a second flexible element (whichis also easily maneuvered independently) at an angle to or a distancefrom the first flexible element such that the tissue modificationportions of the flexible elements are adjacent to one another and adistance apart (e.g. a distance substantially equal to the width of thefacet joint or the width of an interbody fusion device) and may modify aportion of tissue substantially equal to that distance. In someembodiments, the two flexible elements function to cut a strip of targettissue having a width substantially equal to the distance between theflexible elements.

Delivery Devices and Methods

FIG. 44 illustrates an embodiment of a delivery device for delivering atissue modification device for removing tissue from a patient. In someembodiments, the device includes a ribbon shaped flexible elongate body4401 having a width defined by a first edge 4402 and a second edge 4403.In some embodiments, the first and second edges are substantiallyparallel. The device may also include a first channel disposed along aportion of the length of the elongate body, positioned toward the firstedge of the elongate body, and a second channel disposed along a portionof the length of the elongate body, positioned toward the second edge ofthe elongate body. As shown, the channels may be made up of elements4404 and 4405. Alternatively, the channels made comprise a singletubular element (not shown). The channel is sized and configured toreceive two elongate cutting members 4406. In some embodiments, thedevice may also include a guidewire coupler (not shown) at the distalend region of the elongate body 4401.

Also described herein are methods for delivering tissue modificationdevices for removing tissue from a patient. In some embodiments, themethods include the steps of inserting an elongate, flexible shield 4401into the patient at a first location; advancing the shield until aportion of the shield is adjacent to a target tissue; inserting a firstelongate, flexible cutting element 4406 through the shield until aportion of the first cutting element is adjacent to a target tissue;inserting a second elongate, flexible cutting element 4406 through theshield, a distance from the first cutting element and substantiallyparallel to the first cutting element, until a portion of the secondcutting element is adjacent to a target tissue; and modifying the tissuewith the flexible elements.

In some embodiments, the methods include the steps of inserting a firstelongate, flexible cutting element 4406 until a portion of the firstcutting element is adjacent to a target tissue; advancing an elongate,flexible shield 4401 into the patient, wherein a portion of the shieldis advanced over the first elongate, flexible cutting element; insertinga second elongate, flexible cutting element 4406 through the shield, adistance from the first cutting element and substantially parallel tothe first cutting element, until a portion of the second cutting elementis adjacent to a target tissue; and modifying the tissue with theflexible elements. In some embodiments, the methods further include thestep of removing the shield 4401 from the patient while leaving thecutting elements in position within the patient.

Various embodiments of tissue modification devices and systems, as wellas methods for making and using tissue modification devices and systems,are provided herein. In general, a flexible tissue-modification deviceas described herein is configured to remove tissue from a patient. Inparticular, these tissue-modification devices may be configured toperform tissue removal such as a Facetectomy. These devices typicallyinclude a flexible elongate body that extends proximally to distally(proximal/distal), and is configured to be inserted into a patient sothat it extends around the target tissue (such as a facet joint of thespine), so that it can be pulled against the target tissue by applyingtension to either end of the device. Thus, the device may be extendedinto or through a spinal foramen, and/or around a spinal facet joint.

Although much of the following description and accompanying figuresgenerally focuses on surgical procedures in spine, in alternativeembodiments, devices, systems and methods of the present invention maybe used in any of a number of other anatomical locations in a patient'sbody. For example, in some embodiments, the flexible tissue modificationdevices of the present invention may be used in minimally invasiveprocedures in the shoulder, elbow, wrist, hand, hip, knee, foot, ankle,other joints, or other anatomical locations in the body. Similarly,although some embodiments may be used to remove or otherwise modifyligamentum flavum and/or bone in a spine to treat spinal stenosis, inalternative embodiments, other tissues may be modified to treat any of anumber of other conditions. For example, in various embodiments, treatedtissues may include but are not limited to ligament, tendon, bone,tumor, cyst, cartilage, scar, osteophyte, inflammatory tissue and thelike. Non-target tissues may include neural tissue and/or neurovasculartissue in some embodiments or any of a number of other tissues and/orstructures in other embodiments. Thus, various embodiments describedherein may be used to modify any of a number of different tissues, inany of a number of anatomical locations in the body, to treat any of anumber of different conditions.

The examples and illustrations included herein show, by way ofillustration and not of limitation, specific embodiments in which thesubject matter may be practiced. Other embodiments may be utilized andderived there from, such that structural and logical substitutions andchanges may be made without departing from the scope of this disclosure.Such embodiments of the inventive subject matter may be referred toherein individually or collectively by the term “invention” merely forconvenience and without intending to voluntarily limit the scope of thisapplication to any single invention or inventive concept, if more thanone is in fact disclosed. Thus, although specific embodiments have beenillustrated and described herein, any arrangement calculated to achievethe same purpose may be substituted for the specific embodiments shown.This disclosure is intended to cover any and all adaptations orvariations of various embodiments. Combinations of the aboveembodiments, and other embodiments not specifically described herein,will be apparent to those of skill in the art upon reviewing the abovedescription.

1. A bimanually controlled tissue modification device having a tissuemodification region for cutting tissue in a patient, the tissuemodification region comprising: a pair of flexible elongate cuttingmembers extending along the length of the tissue modification region,wherein each elongate cutting member has a thickness and each elongatecutting member is configured to cut a discrete trough into tissue to adepth that is greater than the thickness of the cutting member.
 2. Thedevice of claim 1, further comprising a guidewire coupler distal to thetissue modification region of the device.
 3. The device of claim 2,wherein the guidewire coupler is configured to be coupled to aguidewire, and wherein the tissue modification region is configured tobe actuated by a proximal handle and a guidewire.
 4. The device of claim1, wherein the tissue modification region is configured to be actuatedby a proximal handle and a distal handle.
 5. The device of claim 2,wherein the guidewire coupler is configured such that the device isremovably attachable to a proximal end region of a guidewire such thatthe tissue modification region can be pulled into position by pulling onthe guidewire while the proximal end region of the guidewire is heldstationary by the guidewire coupler with respect to the device.
 6. Thedevice of claim 1, wherein at least one cutting member comprises acutting wire.
 7. The device of claim 1, wherein at least one cuttingmember comprises an elongate wire having a helical cutting edge alongthe length of the wire.
 8. The device of claim 1, further comprising aspacer coupled to the elongate cutting members of the tissuemodification region, wherein the spacer is sized and configured totemporarily hold the cutting members a distance from one another.
 9. Thedevice of claim 8, wherein the spacer comprises an elongate, flexible,ribbon-shaped substrate.
 10. The device of claim 9, wherein the spacerfurther comprises a restraint located towards the outer edge region ofthe spacer and configured to temporarily secure a cutting member to theouter edge region of the spacer.
 11. An elongate, bimanually controlledtissue modification device for cutting tissue in a patient, the devicecomprising: a pair of flexible, elongate cutting members extending alongan elongate length of the device; and a spacer, wherein the spacer issized and configured to operate in one of two modes: a first mode,wherein the spacer is coupled to the cutting members such that it holdsa portion of each of the two cutting members a distance from oneanother, and a second mode, wherein at least a portion of the spacer ismoved away from a cutting member to allow the cutting members to cutfurther into tissue.
 12. The device of claim 11, wherein the elongatecutting members are substantially parallel to one another.
 13. Thedevice of claim 11, wherein the spacer in the second mode is positionedout of the plane of the cutting members.
 14. The device of claim 11,further comprising a guidewire coupler at the distal end region of thetissue modification device.
 15. The device of claim 11, wherein thespacer in the second mode is positioned such that each of the cuttingmembers can cut a depth into tissue that is greater than the thicknessof the cutting members.
 16. The device of claim 11, wherein the spacerfurther comprises a restraint configured to couple the spacer to acutting member while the spacer is in the first mode.
 17. The device ofclaim 11, further comprising a spring, wherein the spring is configuredto expand as the spacer transitions from the first mode to the secondmode.
 18. The device of claim 11, wherein the cutting members are sizedand configured to cut a first depth into the tissue while the spacer isin the first mode and to cut a second, greater depth into the tissuewhile the spacer is in the second mode.
 19. The device of claim 11,wherein the cutting members are configured to be actuated by a proximalhandle and a distal handle.
 20. A method of modifying tissue, the methodcomprising: passing an elongate, flexible tissue-modification device atleast partially around a target tissue, moving a tissue-modificationregion of the device against the target tissue by pulling thetissue-modification device from at least one end of the device; andcutting two discrete elongate troughs into the tissue with a pair offlexible elongate cutting members extending along the elongate length ofthe tissue modification region, wherein the elongate cutting membershave a thickness and each of the elongate troughs are cut to a depththat is greater than the thickness of the cutting members.